Reversible hammer mill with material-deflecting feed structure



July 4, 1950 wlusioN 1 REVERSIBLE Hmm um. mma :MATERIAL-.DEFLECTING :man STRUCTURE Filed Feb. 17, 194s--A 2 Shoets-Sheet 2 IN VEN TOR.

Patented July 4, 1950 REVERSIBLE HAMIVIER RIAL-DEFLECTING FEED STRUCTURE John Gilmore Wilson, Malvern, Pa., assigner to Pennsylvania Crusher Company, Philadelphia, Pa., a corporation of New York Application February 17, 1948, Serial N0. 8,831

2 Claims. l

This invention relates to reversible hammermills for instance as illustrated in the patent of- W. A. Battey No. 2,149,571, issued March 7, 1939. and of Stanley D. Hartshorn, No. 2,170,407, issued August 22, 1939.

It is an object of this invention to provide a reversible hammermill of this type having means for arresting the escape of dust and deilecting particles from passing out through the entrance feed.

These and other objects of this invention will be better understood from the following detailed description of the specic embodiment with reierence to the accompanying drawings oi' which:

Fig. 1 is a sectional view of the upper part'oi.' a reversible hammermill showingthe dust arrester; and

Fig. 2 is a side sectional view of the reversible hammermill taken on line II-Il of Fig. 1.

The machine shown in Figs. 1 and 2 comprises a frame i which supports and encloses the crushing machinery.

Supported within the frame I0 is a cage II formed by left breaker plates I2, I3 and I4 and right breaker plates I6, il Iand I8, and screen bars i@ and 2l, and frame liners 22. The screen bars I8 and 2l are pivoted on cage hinge shafts 2,3, and enclose a hammer mechanism 24. The

m u mechanism 24 is composed of hammers 26 fastened on a rotary shaft 2l through disks 26 and hammer suspension bars 32. The disks it. are regularly spaced along shaft 2l by spacers 26 and the disks 28 at each end abut againgt collars 3l on the shaft 21. The hammer suspension bars 32 extend longitudinally through suitable holes in the disks 28 at regularly spaced intervals around the circumference oir these disks. The hammers 26 are pivoted on the bars 'The frame I0 has a hopper or feed chute 3l centrally positioned on its upper side to feed material to be crushed through a hopper liner I4 into the cage II above the hammer mechanism 24. The shaft 21 is suitably driven by means not shown to rotate the hammers 26 in either direction.

The breaker blocks are arranged symmetrically on each side of the cage II to receive the material to be crushed upon rotation of the hammer MILL WITH MATE- troduced through hopper Il is crushed and reduced in a manner illustrated and described 'in U. S. Patent No. 2,170,407 to Stanley D. Hartshom, issued August 22, 1939.

As the hammers 26 rotate and crush the material small particles of dust formed during the crushing operation are thrown or risc from the crushing operation and escape through the hopper 33. According to this invention, to prevent this escape of dust and other small particles. f a plate 36 is provided which abuts against the upper breaker block I2. This plate 36 has arms 31. Each oi' the arms Il receives a shaft 3l which extends from the side of the frame vIl passing through suitably provided apertures in the frame I8 and the hopper liner 34. The baille 39 comprising the plate 36 and the arms 31 is centered in the upper part of cage II immediately above the hammer mechanism 24 and with a minimum clearance above the outermost extremity of the path of the hammers 2l. One side of the plate 36 abuts against the upper breaker block I2 and extends into the cage Il obliquely at an acute angle to the vertical dimension of the hammermill and substantially perpendicular to a tangent to the path oi the hammers 26; An arm 4I is fastened on the outer end oi' one o! the shafts Il and suitably spaced away from the frame l0 by a sleeve 42. The arm 4I is provided at its end with a bracket 43 suitable for securing the arm M in place. The cage il above the hammer mechanism 24 is symmetrical and spacious so that the hammers may rotate in either direction and impact the material to be crushed on either side. The impacting zone atthe top ot cage Il is thus divided into a chamber 46 on the right side as shown in Fig. 1 for the impacting upon clockwise ro'- tation of the hammer mechanism 24 and a chamber 44 on the lett side as shown in Fig. 1 for impactingupon counterclockwise rotation of the hammer mechanism 24. The shafts 38 turn in the hopper-linerZl and the frame I6 to swing the plate "into contact with either the breaker block I2 in the chamber 46 or the breaker block Il in the chamber 44. The bracket 43 is fastened to frame III by suitable means not shown so as to hold plate I6 close to one or the other o! the breaker blocks I 2 and Il.

mechanism 24 in either direction. Material in- .50 The baille t! may be set withthe plate 36 tting either breaker block i3 or breaker AsshowninFig. Lthebaiile 33 isfaswith the plate 33 abutting the left breaker I3 in chamber 43. In operation the ham- 33 engage the material to be crushed which fed through hopper 33 into the cage il and as own in'Pig. l is implicated and thrown against the right breaker blocks il, l1 and i3 for reduction. As described in the Hartshorn Patent No. 2,170,407 above referred to. the material is further reduced and removed from the hammermill by screenbars l3and3| ofthecage Il. The rapidly moving hammers 33 rotating in the cage Il produce a current of air which travels upward with the rising side of the hammer mechanism 23. This current of air enters the large impacting none and sweeps tangentially from the circle of hammer rotation roughly following the contour of chamber 43. In the absence of the device of this invention the current of air escapes from the chamber 43 passing upward and out through the feed hopper 33 causing a back draft out of lthe hopper which retards the feeding of uncrushed material. Dust formed during the reduction operation and carried around in this current of air also passes out through hopper 3 3. At the high operational speed of the hammermill small particles are thrown oi tangentially from the hammers. Some of the particles that are thrown oi! when the hammers are passing through the upper portion of the cage Il fly upward into the hopper 33 and also escape out of the top. This back draft and escape of dust and small particles is objectionable. As provided for by this invention in prevention of these objections, the plate 33 extends across the chamber 43, as shown in Fig. l, from the breaker block I2 to a line immediately adjacent the outer diameter of the path of the rotating hammers '33. The plate 3i together with the chamber 48,

as sha by the breaker blocks l2 and I5, form a recegseiln which the upward travelling current of air from the hammers 26 sweeps around in a semicircle and is deflected by the plate 36 away from the hopper 33 and back into the circle of hammer rotation where itbecomes part of the air travelling with the hammers 2B. Concomitantly, the hammers 2S as they pass the lower edge of the 'plate 3i reduce the pressure on the side of the plate 36 near the hopper 33. The reaction froxn this lowered pressure increases the down draft through the hopper and further inhibits escaping particles. On the other hand, the baille 33 constricts the air current passing through the chamber 48 to build up a pressure on the opposite side of the baille 39 in the chamber 33.' This pressure tends to back up into the screen bar sector of the cage Ii and force the air to escape through the screen bars I9 and 2i and thus cut down the volume of air which tries to force its way into chamber 3! and out through hopper 33. Small particles tangentially catapulted from the hammers 26 strike the plate 38 when released in the chamber 43 and are deected downward toward the screen bars I8 and 3l.

When the hammermill is reversed so that the 4hammers run in a eounterclockwise direction an identical operation of the baille 33 may be obtained by reversing its position to the right of cage Ii in chamber M. as shown in Fig. l, and into engagement with the breaker block II. The bracket 43 is'suitably fastened in this -position and the above described operation of the hammermill will be obtained in the reverse direction.

The plate 33 in addition to deeeting inwa-riiLif the dust particles rising from below also will serve to deilect the particles of the material to be crushed introduced through hopper 33. This is of advantage as in a hammermill the penetration of the crushed material beyond the outer edge of the face of the rotating hammer is important in reducing the attrition on the hammer and consequently lengthening its life. The plate 36 engaging the material as it comes through the hopper 33 and deilecting it to a place of engagement with the hammers 33, which place of engagement is behind the place where the material would engage the hammers were it not for this denection, permits the material to drop further down onto the face of the rotating hammers 36.

This invention prevents the dust and small particles, formed when material such as coal is broken in a hammer-mill, from rising back out oi the feed hopper and at the same time does not impede the feeding of the material to the hammers. Thus it separates the objectionable back draft of air, dust and small particles from the descending feed and directs both into the rotor. A hammermill operating without the device oi this invention permits objectionable dust and small particles to escape from the feed hopper. The advantage of this invention is that the baille reduces the back draft of air and deiiects the current of dust-carrying air and small particles thrown off from the hammers back into the hammers from which they pass out through the screen bars I9 and 2 i The recesses formed by the walls of the chambers Il and 46 in combination with the plate 36 is advantageous as it swirls dustcarrying air current around and back into the circle of hammer rotation without forcing the current of air to seek outlet elsewhere. The'lowered pressure in the hopper further Iinhibits escaping particles. The device of this invention is also advantageous mits reversibility which places it in the most advantageous position during the operation of the hammermill in either direction and removes it from the path of the impacted material when not used on that side of the hammermiil.

It is to be understood that the baille may consist simply of a plate placed in position to deect the particles and back draft and create a down draft. The manner, as described, of positioning the baille will suggest various ways by which the baille may be moved or arranged. It will be apparent to those skilled in the'art that various modications can be made without departing from the principles of the invention as disclosed herein and for that reason it is not intended that it should be limited other than by the scope of the appended claims.

What is claimed is:

1. In a crusher a rotor having hammers adapted to receive and impact material entering vertically downward at top center of the hammer circle, a feed chute radially above said center and having its lower end in a definite xed position spaced from the hammer circle to provide an intermediate chamber for central radial supply of the material from the chute into said hammer circle, a stationary breaker plate structure beginningat least at the said stationary lower end of said feed chute and extending along the side of said chamber, and a deilector plate at the side of said chamberl interposed between said rotor and said breaker plate and extending from said jacent said hammer circle to intercept material from the side of said chamber and directl it inward into the hammer circle.

2. A Crusher as set forth in claim 1 in which the rotor is reversible with breaker plates on each side of said chamber and the deector is mounted on a movable support positioning said deflector interchangeably in said intercepting position at each side of the chamber.

J. GILMORE WILSON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 640,845 Webster Jan. 9, 1900 675,751 Moustier June 4, 1901 Number Number 

